There's a halfway-decent chance that if you eat cashews, at least some of them have come from Tanzania. As of the most recent available data in 2010, they rank 9th in world production (though they're sliding down the rankings as the cashew trees age). It's also one of Tanzania's main cash crops, making up about 5% of the country's GDP. Farmers depend on the crop and the proceeds from selling it to get themselves out of poverty. (And you know what 'poverty' means in African terms.)
So when the co-op to which the farmers in the southeastern district of Liwale have sold their cashews suddenly pay them less than half the amount they had previously agreed to on claims that the world cashew market had fallen- which it has, but it just fell along with the rest of the global economy and that was four and a half years ago- one might expect the farmers to not take it well. In this instance, with some 5,000 farmers having been kept waiting for full payment since October (they were supposed to get paid in two installments; the first was paid last year and the second installment is what they're waiting on), 'not take it well' can be taken to mean 'riot in the streets, hunt down and burn 24 buildings, making sure the houses of government officials they figure could have gotten them their money are among them'. The officials targeted were members of the ruling party, Chama cha Mapinduzi (or CCM). There are 19 reported arrests; no casualties.
The matter has been exacerbated by the fact that cashew nut processing factories are failing to find funding, and existing factories are being converted to warehouses. The collateral that banks are asking to fund the construction of factories is getting to be too high for investors to afford. As a result, processing has been outsourced and India, a riser in cashew production and currently second behind Nigeria, is taking advantage.